Dear Mr. Dad: I hope this doesn’t sound too crazy, but here goes. My 7-year old son has been telling me for a while that he “hears colors.” I asked him what he meant and he told me that when he says the alphabet or counts, or when people say certain words, he sometimes sees colors. At first I thought he might be having some kind of hallucinations, but he seems perfectly fine in every other area of his life. Is this anything to worry about?

A: From what you describe, it sounds like your son may have a neurological condition called synesthesia. That’s when stimulating one sense—such as your son’s sense of hearing—also triggers the sensation of another one—the colors he perceives. (I have to admit that I only recently learned about synesthesia while doing an interview with Maureen Seaberg, the author of a fascinating book called, Tasting the Universe.

While synesthesia is a condition, it’s by no means a disease. In fact, many see it as a gift, and research shows that synesthetes (people who have synesthesia) often have higher-than-average IQs. While the condition (there’s that word again) may affect as much as five percent of the population, it tends to run in families, and it’s much more common among artists, writers, other creative people (synesthetes are also more likely to be left handed.)

There are actually quite a few different types of synesthesia which can involve any of the senses (although usually only two at a time). Some find that reading, saying, or even thinking certain words triggers a taste, which may explain why these folks sometimes have trouble focusing on what they’re reading. Others, like your son, see colors when they read. Still others hear sounds when they move in certain ways or even see certain kinds of movement. Personally, I find this stuff absolutely fascinating.

What’s especially interesting is that for kids, the connection between the senses may change—the numbers your son sees as turquoise today may be a different color later. But in adulthood, things solidify. For example, if the word antelope is blue or smells like licorice, or if Lady Gaga’s voice tastes like strawberries, it always will.

Quite a few famous people have or had synesthesia. In an interview with Seaberg, violinist Itzhak Perlman says that when he plays a B-flat on the G string he sees a deep forest green, while an A on the E string is red. Musician and producer Pharnell Williams (who’s written songs for Justin Timberlake, Madonna, Britney Spears, Gwen Stefani, Nelly, and many more) says that his music-to-color synesthesia is his “only reference for understanding.” Nobel laureate physicist Richard Feynman saw equations in color. And actress Tilda Swinton hears food: The word “table,” for example, tastes like cake, while the word “tomato,” reportedly tastes like a lemon instead of, well, a tomato.

So the bottom line is that unless your son’s affects your son’s life in a negative way, there’s nothing to worry about. But if you truly are worried, ask your pediatrician for some guidance. If you’re interested in finding out more about synesthesia on your own, Tasting the Universe is a great place to start. The Synesthesia Resource Center (bluecatsandchartreusekittens.com) has all sorts of tasty pieces of information. You might also want to have your son take the synesthesia battery at synesthete.org. In fact, take it yourself.